This invention relates to shock-activated electrochemical power supplies. Various types of electrochemical power supplies have long been known in the art. One such electrochemical power supply is known as the thermal battery and comprises at least one electrochemical cell comprising a cathode, an anode and an electrolyte which is inactive at ambient temperatures but which is rendered active at higher temperatures. Such thermal batteries frequently employ a solid electrolyte formed from a eutectic mixture of one or more materials which are electrochemically inactive when solid but which become electrochemically active when molten. The means for activating such a thermal battery is generally a pyrotechnic heat source. The battery is activated by igniting the pyrotechnic heat source which heats the electrolyte causing the electrolyte materials to fuse and become a highly conductive fluid. See, e.g., The Primary Battery, Cahon, et al., John Wiley & Sons, 1976, Chapter 6; and Japanese patent No. 021,098, Aug. 26, 1972.
Thermal batteries have several advantages over simple galvanic and acid batteries. They exhibit long stand times and can be activated when an electrical current is desired, but until such time as such a battery is activated it remains inactive and chemically inert. Despite these advantages thermal batteries possess inherent disadvantages. Particularly disadvantageous is the fact that the initiation time of such batteries, i.e., the time required to render the electrolyte active, is limited at the lower end to the time required to ignite the pyrotechnic device and the time required to transfer the resultant thermal energy to the electrolyte. Thus, conventional thermal batteries are undesirable in situations where extremely rapid initiation times are desirable.
Shock-activated power sources are also known in the prior art. Prior art shock-activated power supplies employ an active signal generating element such as a piezoelectric crystal or ferroelectric or ferromagnetic circuit. However, such prior art systems are disadvantageous in that they produce an electric current or signal only during the time the pressure or shock is applied to the active element. Thus, such prior art shock-activated power supplies provide an electrical pulse having a duration of, e.g., only a few microseconds.